1. Field of the Invention
The present invention relates to an expiration collector for collecting expiration from a subject as a sample, for analyzing the expiration sample in an analyzer such as a gas chromatograph.
2. Description of the Background Art
A clinical test for diagnosing, curing or preventing a disease is generally made on blood or urine. On the other hand, expiration is employed in the laboratory level as a specimen for a clinical biochemical test other than those for blood and urine, leading to such recognition that expiration also includes information as to a disease. The expiration test has such an advantage that the expiration can be collected at any time in a painless manner.
Methods of collecting a specimen of expiration for measuring components of the expiration specimen by an analyzer such as a gas chromatograph are roughly classified into three types, i.e., a chemical trap method of blowing expiration into a solvent for dissolving the former in the latter, a cold trap method of blowing a large amount of expiration into a cold trap which is cooled to about -80.degree. C., for example, for condensing the same, and an adsorption trap method of adsorbing expiration components to an adsorption trap which is charged with activated carbon or adsorption resin (Scientific American, July 1992, pp. 52-57). Among these, the cold trap method and the adsorption trap method have already been put into practice.
In the cold trap method, the sample as trapped is generally partially injected into a gas chromatograph through a micro syringe, to be subjected to analysis. However, it is extremely difficult to put this method into practice as clinical test means for a hospital routine which must be quickly and readily carried out while bringing the analyzer into the bedside of a patient.
In the adsorption trap method, expiration components which are adsorbed by the trap are heated and desorbed to be introduced into a gas chromatograph. However, this method is not suitable for a clinical test for a routine which must be quickly and readily carried out while bringing the analyzer into the bedside of a patient either, in addition to such an essential problem that adsorptivity of the adsorption trap is varied with the components.
In expiration which is subjected to analysis, an initial part containing air from a dead space is eliminated so that a part called end-tidal air is most suitably employed as a sample for the analyzer. The end-tidal air, which contains only alveolar air with homogeneous concentration of expiration components, is excellent as a specimen. In an expiration test, therefore, the end-tidal air is measured as the most reliable specimen expressing the state of the subject, while a specific apparatus is required for collecting the end-tidal air.
On the other hand, the method of collecting the expiration by blowing the same into an apparatus is applicable only to a conscious subject. For example, it is difficult to correctly collect expiration from a subject who is unavailable for communication such as a baby, a child, a soporose patient or an unconscious patient. If the subject is healthy but old, for example, it may also be difficult to test the end-tidal air in consideration of his physical strength.
A gas measurer such as a gas chromatograph is now being put into practice as a clinical test appliance with improvement of sensitivity, miniaturization and a technique of implementing portability. When such a gas measurer is applied to an expiration analyzer for carrying out a quick clinical test, it is necessary to simply collect expiration in a gas state without trapping the same by a cold trap or an adsorption trap, for directly guiding the expiration to the analyzer so that reliable test data can be obtained in a short time. In order to attain high practicality of such a clinical test appliance, it is necessary to simplify the operation for collecting expiration which is employed as a specimen.